1. Field of the Invention
The present invention relates to an extension spring installation structure for installation of one or more extension springs adopted to eliminate backlash in a lens barrel.
2. Description of the Related Art
Play (backlash) is structurally indispensable between two members movably sliding on each other. However, since backlash concurrently has an influence on the accuracy of movement of the movable members, various types of backlash eliminating structures or mechanisms have been proposed. For instance, a backlash eliminating structure which eliminates backlash between two members (e.g., lens group support frames) which are movable relative to each other by the use of extension springs which bias the two members in directions to approach each other is known in the art.
Each of the aforementioned extension springs is unstable and easily comes off until opposite ends of the extension spring are seated over hooked portions of the aforementioned two members, respectively. Accordingly, it is conventionally the case that the opposite ends of the extension spring are simultaneously seated over the hooked portions of the two members, respectively, or that one of the opposite ends of the extension spring which is firstly seated over the associated hooked portion is cemented thereto before the other end of the extension spring is seated over the associated hooked portion to prevent each end of the extension spring from coming off the associated hooked portion unintentionally. However, such an extension spring installation manner is troublesome, and accordingly, there has been a demand for an improved extension spring installation method which is far superior in regard to ease of installation compared to conventional extension spring installation methods.